Self-Spinning Seat Solution for Remigiusz

  • Context: High School 
  • Thread starter Thread starter remi_c
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Discussion Overview

The discussion revolves around the design of a self-spinning seat intended for a student project, which is to be suspended from a rope and spin slowly when a person sits on it. The scope includes conceptual exploration of mechanics and potential materials for the construction of the seat.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Remigiusz seeks a solution for a self-spinning seat that spins slowly when weight is applied, returning to its original position afterward.
  • One participant suggests that there may be a violation of the Second Law of Thermodynamics involved in the proposed mechanism.
  • Another participant notes that a twisted rope could create rotational oscillation when stretched, but it would not stop immediately after the weight is removed.
  • A participant compares the desired motion to that of a swing, questioning whether the mechanics would be similar.
  • Remigiusz clarifies the intent for the seat to return to its original position, correcting an earlier misunderstanding about indefinite spinning.
  • There is a discussion about the challenges of using twisted ropes, which would untwist rather than return to shape, and the idea of using a single material, specifically a rope, for the design.
  • Remigiusz expresses interest in understanding the mechanics of how a heavy platform on a long rope moves and spins when a person shifts their position.
  • Some participants engage in light-hearted banter, which diverges from the technical discussion.

Areas of Agreement / Disagreement

Participants express various ideas and concerns regarding the mechanics of the proposed seat, with no consensus reached on the feasibility or design specifics. The discussion remains exploratory with multiple competing views on how to achieve the desired motion.

Contextual Notes

Participants have not fully resolved the implications of using twisted ropes or the mechanics of the proposed design, leaving several assumptions and conditions unaddressed.

remi_c
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"Self-spinning" seat

Hi,

I'm looking for a solution for my student project. I thought maybe I would find it here :)

I am currently doing a place to rest in a forest. The "seat" will weight about 50 kilograms (ca. 100 pounds) It will be hung on a 10-15 meter-long rope (30-45 ft.).

The seat is to not move until someone gets on it. Then, it has to spin slowly under the influence of weight (it means up to 1/8 spin per second) - periodicaly rigt, then left and so on. Obviously, after that it would return to the original position. I haven't found out yet, how to make such a rope. Does anyone have an idea? I would be grateful for any hints.

Thanks,
Remigiusz
 
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It sounds to me as if there would be a violation of the Second Law invlolved, but I'll think on it a mite.
 


A twisted rope rotates when stretched. You'd basically be using the weight of the person sitting down to make the thing oscillate rotationally. Though, once the person gets off, the thing won't stop immediately. It will go on swinging back and forth for a while.
 


remi_c said:
it has to spin slowly under the influence of weight (it means up to 1/8 spin per second) - periodicaly rigt, then left and so on.

Isn't this what happens when we dangle on a swing? i.e. two ropes?
 


I just re-read the original post and realized that I made a mistake in having missed the part about it returning to its original position. For some reason, I thought that the intent was for the thing to continue spinning indefinitely. Sorry.
 


I want to an effect of a dangling swing - however, instead of swinging from side to side I want it to swing left and right. Twisted ropes would work, but they won't come back to the previous shape - they will just "untwist".

The only thing that comes to my mind is to hang the seat on some kind of a long spring - but I should rather use only one material - a rope.

The other thing is, that when a person sits on a heavy "platform" hung on a long rope, it will move randomly - and it will also spin a bit.The spin rate changes when a sitting person changes position - when she stretches her hands and legs, it moves faster... (have you ever swirled on a tyre hung on a tree...) Do you know how it happens? I must learn everything about this "phenomena".

Please write when you have anything interesting on your mind. Thanks!
 


remi_c said:
Please write when you have anything interesting on your mind. Thanks!

I always have something interesting on my mind; it just might not coincide with your interests.
 


remi_c said:
...instead of swinging from side to side I want it to swing left and right...

Now this is interesting... :rolleyes:
 


Dr Lots-o'watts said:
Now this is interesting... :rolleyes:

Pervert!

And I don't mean that in a bad way.
 
  • #10


Uhhh... I think I'll leave you two alone now... :wink:
 
  • #11


Dr Lots-o'watts said:
Uhhh... I think I'll leave you two alone now... :wink:

Don't bail so fast, Sweetie. What made you think that I was referring to Remi?
 

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